Semi-selective media for the isolation of Phaeomoniella chlamydospora from soil and vine wood.

Abstract

Two semi-selective culture media, F10S (PDA + folpet 10 ppm + streptomycin sulphate 1 g l -1 ) and RB150S (PDA + rose bengal 150 ppm + streptomycin sulphate 1 g l -1 ), were developed for the isolation of the phytopathogenic fungus Phaeomoniella chlamydospora from soil samples and vine tissues. The media were selected so that they would allow proper growth of the pathogen and would partially inhibit eleven other common fungal genera. Eight antifungal agents were tested: Folpan (a.i. folpet), Captazel (a.i. captan), Benlate (a.i. benomyl), Chipco (a.i. iprodione), Switch (a.i. cyprodinil + fl udioxonil), rose bengal, and the bactericidal antibiotic streptomycin sulphate at several doses. Recovery of Pa. chlamydospora from wood samples was 40% better on RB150S and 50% better on F10S than on PDA, while the contaminants were reduced by 42% with RB150S, and by 48% with F10S. Pathogen reisolation from artificially contaminated soil samples was improved with F10S, while RB150S facilitated pathogen detection in samples containing moderate amounts of Rhizopus, Trichoderma, Penicillium, Alternaria or Trichoderma or in soils heavily contaminated with bacteria. F10S and RB150S improved the isolation of Pa. chlamydospora from wood and soil and can be used as alternatives to current culture media.